Standard enthalpies of formation of finite-length (5,5) single-walled carbon nanotube

Standard enthalpies of formation (Delta H-f(0)) of finite-length ( 5, 5) single- walled carbon nanotubes ( SWNTs) are calculated with the framework of density functional theory. Approximate expressions of (Delta H-f(0)) have been proposed for both H-terminated and C30- capped ( 5, 5) SWNTs, based upon which the calculated values of (Delta H-f(0)) have been reproduced within several kilocalories per mole. It is also found that standard enthalpies of formation contributed by per carbon, Delta H-f(0) (C), oscillate with the increment of the cluster size, suggesting the dependence of the relative stability on the axial length

The seroepidemiology of Immunoglobulin G antibodies against pertussis toxin in China: a cross sectional study

<p>Abstract</p> <p>Background</p> <p>Pertussis is a reported vaccine-preventable respiratory disease in China. Because the routine laboratory methods for diagnosis are not in use, the reported cases are mainly in infants with classical paroxysmal cough and the true incidence related to pertussis is most likely under estimated. In China, however, few studies have attempted to address this issue. The purpose of this cross sectional study was to estimate the incidence rates using the method of sero-epidemiology of immunoglobulin (Ig) G antibodies against pertussis toxin (PT) among healthy populations in China.</p> <p>Methods</p> <p>Blood samples were obtained from 1313 healthy individuals aged 0 to 95 years in Guangdong province of China throughout September 2010. Serum IgG antibodies against PT were determined by commercial ELISA kits. Subjects with concentration of anti-PT IgG higher than 30 IU/mL were indicated to have recent <it>Bordetella pertussis</it> infection, if they have not received a booster dose of pertussis vaccine within one year.</p> <p>Results</p> <p>Of the 1313 study subjects, 117 (8.91%) were found to have anti-PT antibodies higher than 30 IU/mL. The estimated incidence of recent infection was thus 9395 per 100,000 for individuals older than 7 years. Peaks of the estimated incidence rate of recent infection were found to be 11561 per 100,000 in age group of 41–50 years and 11428 per 100,000 in the group aged 13–19 years.</p> <p>Conclusions</p> <p>Our study indicated that <it>B.pertussis</it> infections are considerablely common, particularly in adolescents and adults in China. The study also stresses the importance of laboratory diagnosis for pertussis and employment of booster dose of pertussis vaccine in adolescents and adults in this country.</p